The sum of the angle measures of any triangle is 180 degrees. find the angle measures of a triangle if the second angle measures twice the first, and the third angle measures 15 degrees less than the second.
a+b+c= 180 a = ? b = 2a - 10 (twice a minus 10) c = b + 25 (25 more than b) Substitute for b c = (2a-10) + 25 Now substitute back into a+b+c=180 a + (2a-10) + (2a-10+25) = 180 Eliminate the parentheses a + 2a - 10 + 2a - 10 + 25 = 180 Combine like terms 5a + 5 = 180 Subtract 5 from both sides 5a = 175 Divide both sides by 5 a = 35 Substitute into the equation for b. b = 2a -10 = 2*35 - 10 = 70 - 10 = 60 Add 25 to b to get c. c = 60 + 25 = 85Check by adding them up. 35 + 60 + 85 = 180 Done.
